Deployment

You’ve built your smart contract, tested it and built a dapp around it. Now it’s time to deploy.

Productionizing your smart contract for deployment to a network other than your local network requires keeping a few things in mind which we will cover in this chapter.

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Deployment Specifics

Properties

Smart contracts may specify an instance property called properties to specify some or all of the properties used during deployment:

export class Contract extends SmartContract {
  public readonly properties = {
    codeVersion: '1.0',
    author: 'Alex DiCarlo',
    email: 'foo@bar.com',
    description: 'This Contract is the best one.',
  };
}

These properties have no impact on the execution of the contract, they’re simply extra metadata that you may permanently attach to the contract on the blockchain.

Upgrade

Every NEO•ONE smart contract automatically contains a public upgrade method. This method replaces the smart contract code as well as the static metadata associated with the contract while preserving the smart contract’s storage. In other words, this method can be used to change the logic of your smart contract without losing the data.

In order to make it possible to upgrade your contract, you must specify the approveUpgrade public method. This method should return a boolean indicating if the upgrade is approved:

export class Contract extends SmartContract {
  public constructor(public readonly owner = Deploy.senderAddress) {}

  public approveUpgrade(): boolean {
    return Address.isCaller(this.owner);
  }
}

Using Address.isCaller(this.owner) is the most typical approach.

Note

If you do not specify the approveUpgrade method, it is impossible for you or anyone else to upgrade the contract.

Destroy

All smart contracts have a protected method called destroy which any method may use to permanently delete the smart contract. Once destroy is called the smart contract can no longer be invoked and the storage is no longer accessible. You’re not required to have a method that calls destroy, but if you do, it should probably look something like:

export class Contract extends SmartContract {
  public constructor(public readonly owner = Deploy.senderAddress) {}

  public permanentlyDestroy(): boolean {
    if (!Address.isCaller(this.owner)) {
      return false;
    }

    this.destroy();

    return true;
  }
}

Note

While the contract can no longer be invoked and the storage is not accessible, all of the past invocations still exist on the blockchain. The storage can still be accessed by replaying the blockchain from the beginning up until the point it was destroyed.

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Migration File

To deploy your contract to a network, you will need to define a migration file. The default location for this file is neo-one/migration.ts, but it can be configured. A migration file simply exports a function to call the deploy method on your smart contracts with the appropriate arguments. It should look something like this:

import BigNumber from 'bignumber.js';
import { MigrationContracts } from '../src/neo-one';

export default ({ token, ico, escrow }: MigrationContracts, _network: string) => {
  token.deploy();
  ico.deploy(undefined, new BigNumber(1566864121), undefined);
  escrow.deploy();
};

MigrationSmartContract

You may have noticed the new type we use in the above migration file, MigrationContracts. This is another type generated by NEO•ONE for use specifically in migration files and while it looks the same as its counterpart SmartContract it has a key difference in that there is no .confirmed(...) properties for any of its contract methods. This is because during migration every contract invocation will be be awaited before proceeding to this next invocation. This can be useful when you would like to deploy contracts in series or if you would like to do some additional bootstrapping after the deployment of a contract.

As an example, lets say you have an ICO contract and you would like to make sure you are the first person to mint a portion of the tokens. Then, going off the migration file above, we could run something like:

import BigNumber from 'bignumber.js';
import { Hash256 } from '@neo-one/client';
import { MigrationContracts } from '../src/neo-one';

export default ({ token, ico, escrow }: MigrationContracts, _network: string) => {
  token.deploy();
  // here we set the startTime of the ICO to be immediate
  ico.deploy(undefined, new BigNumber(0), undefined);
  ico.mintTokens([{ amount: new BigNumber(10), asset: Hash256.NEO }]);
  escrow.deploy();
};

This will ensure that after deploying the ico contract (and confirming it is deployed) the next action before deploying the escrow contract is to mint some of the ICO tokens to the currently selected UserAccount. While a more elegant and safe solution might be to allow the owner of the ICO to mint tokens before the timer has started this should make it clear how you can bootstrap a contract during migration.

Deploying to a Public Network

Once you have successfully configured your migration file as explained above you are all set to deploy your Smart Contract! Using the set of networks defined in .neo-one.config.js you can deploy using the command:

yarn neo-one deploy --network <network>

where network is one of the keys provided by your configuration. By default yarn neo-one deploy will use the test key.

Note

We HIGHLY recommend deploying to both a local private network and the Neo TestNet before attempting to deploy to the MainNet.